Transformer construction



Dec. 12, 1939. L. MAUERER 2,183,355

TRANSFORMER CONSTRUCTION Filed Aug. 22, 1938 2 Sheets-Sheet l 7 (9 9 Prmc y 4 L. MAUERER 2,183,355

7 TRANSFORMER CONSTRUCTION Filed Aug. 22, 1958 2 Sheets-Sheet 2 INVENTOR.

leopa/d/yaaeren BY a? ATTORNEY Patented 12 1939 1 H g UNITED STATES PATENT OFFICE 2,183,355 TRANSFORMER CONSTRUCTION Leopold ,Manerer, Chicago, 111. aaignor to Jeflerson Electric Company, Bellwood, 111., a corporation of Illinois Application August 22, 1938, Serial No. 226,064 1z Claims. (01. 171119) An ignition transformer, such as is here c ebarrier of iron or steel will in some instances give picted for purposes 01' illustration, being of the ood results. high reactance type, will cause disturbances in This shield acts in two ways, first, as an eddyspa'rks at the terminals of the secondary winde enclosed in an iron box r c s n nd h ll Another s of disturbance is caused by munication between the compartments resulting l velocity, this causing an extremely high oscilupted y and pos e y Connect he Shield w latory current which is induced by electrostatic the grounding means.

I} actionback into the primary winding, thence to While the magnetic coupling is responsible for the power lines. the transmission of the greater part of the high as the double insulated transformer, in contrato the casing as above referred to. distinction to the grounded type, wherein o ly Better understanding oi the invention will be one electrode is insulated and the other is had from the following if read t h wi h the grounded. Such an insulated type is shown in accompanying drawings in which: 80 the drawings and is here contemplated. Fig. 1 is a plan view of an embodiment of the Unless provision be made to the contrary the de i e with the c er m mber rem vedhigh frequencies so generated will travel along 2 is a Section taken at the line 0f the house wiring circuit and will interfere with i the use and operation of delicate electrical de- 3 i a c o ta e a the e H 0 I vices, such for instance, as radio receiving sets Figand would cause very serious and objectionable Fig. 4 is a per e v View e Sh d ba j noises which would be further amplified through rler em e the audio circuit and resound in the loud speaker, ig- 5 s Vi W S m la o i 2 Of a mOdified thus seriously interfering with radio reception. Struc ure- 40 The high frequency energy conducted through ig- 6 s a d a Se Showing in d ie 4 I the primary and into the house wiring circuit form, a manner of associating the shield member as above referred to may be characterized diflerand the case.

I trical conductivity, and diamagnetic though a stood manner, induce a current flow in the secondary windings i and i which windings will in this case supply a higher voltage through the leads 9 and II. These leads are threaded through bushings II and i2 and supply current to the electrodes of the ignition device (not shown).

A ground connection II is indicated as connected to the middle point I4 of the secondary windings 5 and 6 through a short lead I5 which short lead is connected to the core I (see Figs. 3 and '1).

A shield or barrier I4 is interposed between the primary winding 4 and one of the secondary windings 5, the shield being preferably located adjacent the primary winding 4 and forming a chamber therefor excluding as much of the shunt 3a from. the chamber formed therefrom as possible. This shield I6 is shown in the diagrammatic Fig. 7 as electrically connected by a conductor I1 to the core 3 as at I4 but, as shown in Fig. 3 the sections of conductors I5 and I1 may be continuous, and intermediate its length connected to the case I as indicated at It in Fig. 3.

A clip 20 riveted as at 2| to the shield I4 serves as a means of making a secure connection for the conductor Il.

Flange 22 of the shield I6 serves to securely connect it to the core 3 of the transformer as by the rivets 2323. Flange angles 24 are secured to the casing I and serve as stops or abutments for the edges of the shield and insures a comparatively tight joint along the periphery.

In Fig. 5 is shown a modified form of shielding arrangement in which the shield takes the form of a cup, the bottom portion III and 'the sides of the cup or walls SI surround the primary winding 4; the edges of the walls 3i extend to and contact the casing I through which ground connection is made as by the binding post 25. The bottom portion 30 is further provided with insulation indicated at 32-32.

In Fig. 6 is shown a modified means of forming a connection between the shield I6 and the casing I wherein is provided a groove or channel formed by the angle pieces 2626 which angle pieces contact both sides of the binding 21 which engages the entire periphery of the shield IS.

The structure shown in Fig. 6 will insure close contact of the shield I6 and the case I but will be electrically insulated therefrom by the binding 21 which is secured at the outer edge of the shield I6, and the opening '40 which accommodates the iron core 3 will prevent short-circuiting of the shield I6.

It is regarded as of more importance to seal the shield at its periphery than elsewhere and therefore greater care has been given to accomplish it because the disturbing elements dwell more particularly at the outer strands of the windings.

From the foregoing description it will be understood that in one preferred aspect of my invention, it comprises a transformer adapted to prevent high frequency energy from the secondary winding 5, 6, from radiating to the primary winding 4 and comprising, in combination, a core 3 of magnetic material including a'winding leg 3b and a yoke of magnetic material completing a magnetic flux path, primary 4 and secondary 5, 6 windings surrounding separated portions of the winding leg 3b, a metallic housingi and 2, enclosing the core 3 and windings 4, 5 and 5, a conductive shield I6 extending outwardly from and transversely across the winding leg 3b intermediate the primary 4 and secondary 5, 6 windings,

said shield is extending substantially to the housing I and 2 and having a gap therein to prevent the completion of a continuous short circuited turn around the winding leg 3b, and means comprising a part of said core I substantially closing said gap 40.

In other aspects of the invention, it is pertinent to note that the shield I8 divides the housing I, 2, into two compartments, one compartment containing the primary winding 4 and its lead wires land I. and the other compartment containing the secondary winding I and 8 and its ted leads 9 and I0.

Though I have shown .and referred to an ignition transformer it will be understood that the invention is equally applicable to other high frequency devices and that many changes and modifications may be made without departing from the spiritof the invention.

I claim:

1. A transformer including a magnetic core having a winding leg, primary and secondary windings surrounding the winding leg, a magnetic shunt between the windings for diverting magnetic flux from the secondary winding, a con- I ductive shield disposed around the winding leg between the primary winding and said secondary winding and shunt, and a casing enclosing the transformer, the shield extending to form a partition dividing the easing into two compartments with the primary winding in one compartment and the secondary winding and shunt in the other compartment.

2. A transformer including a magnetic core having a winding leg, primary and secondary windings surrounding the winding leg, a magnetic shunt between the windings for diverting magnetic flux from the secondary winding, a shield of magnetic material disposed around the winding leg between the windings, and a casing enclosing the transformer, the shield extending to form .a partition dividing the easing into two compartments with the primary winding in one compartment and the secondary winding in the other compartment.

3. A transformer comprising, in combination, a core of magnetic material including a winding leg and a yolre connecting the ends of the winding leg to complete a magnetic flux path, a primary winding surrounding said leg, a secondary winding surrounding the leg and adapted to carry high frequency energy in the operation of the transformer, a metallic shield interposed between the primary and secondary windings for intercepting high frequency energy emanating from the secondary winding, and an enclosing metallic casing for housing the transformer, said shield extending to the enclosing walls of the casing and being contiguous therewith to form two compartments,

one compartment containing the primary winding and the other compartment containing the secondary winding.

4. A transformer comprising, in combination, a core of magnetic material including a winding leg and a yoke connecting the ends of the winding leg to complete a magnetic flux path, a primary winding surrounding said leg, a secondary winding surrounding the leg and adapted to carry high frequency energy in the operation of the transformer, a diamagnetic shield interposed between the primary and secondary windings for intercepting high frequency energy emanating from the secondary winding, and an enclosing metallic casing for housing the transformer, said shield extending to the enclosing walls of the casing and 8. A transformer comprising,

winding surrounding said leg, a secondary winding surrounding the leg and adapted to carry high frequency energy in the operation of the transformer, a metallic shield interposed between the ondary winding, an enclosing metallic casing for housing the transformer, said shield extending to and conforming to the enclosing walls of the cas- 6. A transformer comprising, in combination, a core of magnetic material including a winding leg and a yoke connecting the ends of the winding leg to complete a magnetic flux path, a primary winding surrounding said leg, a secondary winding surrounding the leg and adapted to carry high frequency energy in the operation of the transformer, a metallic shield interposed between the primary and secondary windings for intercepting high frequency energy emanating from the secondary winding, an enclosing metallic casing for housing the transformer, said shield extendlng substantially to the enclosing walls of the casing to form two ment containing the primary winding, and the other compartment containing the secondary winding, means electrically insulating said shield from said casing, and electrically conductive means for connecting the shield and core together and to ground.

7. A transformer comprising, in combination, a core of magnetic material including a winding leg, primary and secondary windings surroundlng said leg, a metallic casing housing the transformer, a metallic shield interposed between the primary and secondary windings and dividing with the shield adjacent the cut away portion thereof, and means securing the flange to the core to support the shield.

in combination, a core of magnetic material including a winding leg, primary and secondary windings surrounding said leg, a metallic casing housing the transformer, a metallic shield interposed between the primary and secondary windings closer to the primary winding than to the secondary winding and dividing the said casing into two compartments, said shield being cut away so that the leg extends therethrough and transversely thereto, a flange integral with the shield adjacent the cut away portion thereof, and means securing the flange to the core to support the shield.

compartments, one compart- 9. A transformer comprising, in combination, a core of magnetic material including a winding leg and a yoke connecting the ends of the winding leg to complete a magnetic flux path,

outwardly from said winding leg and shunt to the casing and conforming to the walls of the casing.

11. A transformer adapted to prevent high frequency energy from the secondary winding from radiating to the primary winding and comaround the winding leg, and means comprising a part of said core substantially closing said gap. 12. A transformer and shielding assembly comprising, in combination, a core of magnetic material including a winding leg and a yoke of magnetic material completing a magnetic fiux path, primary ahd secondary windings surrounding separated portions of the winding leg and hav ing leads for making connections thereto, a metallic housing enclosing the core and windings, a conductive shield extending outwardly from the housing and conforming to the housing intermediate the primary and secondary windings, said shield dividing the space Within the housing so that the primary winding and leads are" segregated from the secondary winding and leads, means electrically connecting the shield to the core, and means electrically connecting the shield to the housing.

LEOPGLD MAUERER. 

